"I’ve got some great news – this year, you can look like s**t when you vote,” Katy, who has pledged her support to Democratic Party presidential nominee Hilary Clinton, explains in the video as she whips off her PJs.

She goes on to encourage her fans to make sure they vote in the November poll - even if they do it in their PJs or naked like her.

But it's not the most controversial thing a celeb has done in the name of politics.

Here, we look back at some other extreme political statements celebrities have made…

Kanye West V George Bush

Kanye spoke out against George Bush following Hurricane Katrina [Flynet]

Kim Kardashian's hubby Kanye West expressed his political views in the aftermath of Hurricane Katrina during a live TV interview.

"I hate the way we are portrayed in the media," he fumed. "George Bush doesn't care about black people."

Producers quickly cut to Chris Tucker and changed the subject.

Kanye went on to pen a song, titled George Bush Doesn't Care About Black People, which has been described as "one of the best political protest songs of all time."

Bush responded to the song, saying: "I didn't appreciate it then and I don't appreciate it now. I resent it, it's not true and it was one of the most disgusting moments of my presidency."

Charlotte Church on Austerity

Would you like to see Charlotte Church as a political leader? [ITV]

Welsh beauty Charlotte branded austerity unethical, unfair and unnecessary" at a protest in London in 2015.

"I'm here today in a show of solidarity with everyone here, it is a massive turnout - everybody who thinks that austerity isn't the only way and thinks it is essentially unethical, unfair and unnecessary," she said.

Jennifer Lawrence on the pay gap

Jennifer Lawrence spoke out about the industry's pay gap[Wenn]

Following the Sony Hack, Hunger Games actress Jennifer Lawrence spoke out against the injustice of the Hollywood pay gap.

She said:"When the Sony hack happened and I found out how much less I was being paid than the lucky people with d***s, I didn’t get mad at Sony. I got mad at myself. I failed as a negotiator because I gave up early….But if I’m honest with myself, I would be lying if I didn’t say there was an element of wanting to be liked that influenced my decision to close the deal without a real fight. I didn’t want to seem 'difficult' or 'spoiled.' At the time, that seemed like a fine idea, until I saw the payroll on the internet and realised every man I was working with definitely didn’t worry about being 'difficult' or 'spoiled.'"

Emma Watson on gender equality

In 2014, former Harry Potter star Emma launched her #HeforShe campaign which aims to engage men and boys as agents of change for the achievement of gender equality by encouraging them to take action.

The UN ambassador gave an empowered at the United Nation's headquarters where she insisted things needed to change.

"I am reaching out to you because I need your help. We want to end gender inequality—and to do that we need everyone to be involved," she said.